Let-off mechanism for looms.



Z SHEETS-SHEET 2.

Patented May 20, 1913.

J. H. & H. GREENHALGH.

LET-OFF MBCHANISM FOR LOOMS. APPLICATION` Hub 11111.11, 19104 UNITED STATES 'PATENT OFFICE.

JOHN E. GBEENHALGH, 0F WOONSOCKET, RHODE ISLAND, AND HARRY GBEENHALGH, OF BLACKSTONE, MASSACHUSETTS.

LET-OFF MECHANISM FOB LOOMS.

Specillcation of Letters Patent.

Patented May 20, 1913.

Application lled January 11, 1910. Serial No. 537,515.

To all whom it may concern:

Be it known that we, JOHN H. GREEN- mmn, a citizen of the United States, residing at Woonsocket, in the county of Provldence and State of Rhode Island, and HABRY'GREENHAIAH, a citizen of the United States, and resident of Blackstone, in the county of Worcester and State of Massachusetts, have invented new and useful Improvements in Let-Off Mechanism for Looms, of which the following is a specification.

This invention relates to let-off mechanism for looms, the object of the invention being to provide a simple and effective type of mechanism of this character whereby a uniform tension on the warp threads from beginning to finish of the weaving operation may be secured without the necessity of operating or adjusting levers or other parts or utilizing any positive take-up action, and which is adapted to permit of a freeback- Ward movement of the warps when any amount is picked out.

The invention consists of the features of construction, combination and arrangement of parts hereinafter fully described and claimed, reference being had to the accompanying drawings, in which F 1 is an end elevation showing the apphcation of the invention to a loom frame. Fig. 2 is a top plan view of the letoif mechanism. Fig. 3 is a rear elevation of the drive gearing thereof. Fig. 4 is a section on the line 4-4 of Fig. 2 through the ratchet wheel member of the let-off gearing. Fig. 5 is al transverse section through the transmission gears on the plane indicated by the line 5-5 of Fig. 4. Fig. 6 is an end view of the feed and tension rolls showing the direction of feed movement of the warp threads.

Referring to the drawings, 1 designates the frame of the loom, on which is journaled the driving shaft 2 of the let-off mechanism. This shaft is provided with a hand crank 2 and has loosely mounted thereon a shaft or sleeve 3, provided at one end with a beveled locked together, the shaft 3 will be fixed to the sha t 2 to communicate motion thereto from the shaft 6. The clutch member 10 is feathered to rotate with and slide upon the shaft 2 toward and from the clutch member 7, whereby said clutch members may be thrown into and out of engagement. Said clutch member 10 is adapted to be slidably adjusted by a shipper fork 11 movable in one direction or the other through the medium of an operating lever 12.

Upon the end of the frame opposite the lever 12 open bearings 13 are provided to receive the ends of the shaft 14 of the warp beam or roll 15, which is thus mounted to turn freely in said bearings to permit unwinding of the warp threads 16 therefrom. Arranged above and in advance of the warp roll are guide and tension rolls 17 and 18, the roll 17 being smaller than the roll 18 and disposed in advance of and at a suitable elevation above the lower portion of the periphery thereof. The threads 16, in their feeding operation, are drawn, under the pull of the take-up rollers and beating-in mechanism, from the roll 15 upwardly and rearwardly around the roll 1 and thence rearwardly under and upwardly over the surface of the roll 18, by which arrangement of the two rolls 17 and 18 bights or loops are formed in the threads as they pass therearound, so that an effective feed action is secured, while at the same time the threads are thereby maintained under a pro r tension at all times during the weavlng operation.

One end of the shaft 19 of the Vrimary feed and tension roll 17 has fixed t ereto a pinion 20 which meshes with a gear 21 having an elongated sleeve 22 keyed or otherwise fixed to the adjacent end of the shaftv 23 of the roll 18. Mounted to turn loosely on the hub of this gear 21 is a gear 24 of the same diameter as Said gear 21 and having a hollow body o en at its side facing the gear 21 and closed ereby. On the interior of the rim surface of the gear 24 is formed an annular series of ratchet teeth 25 adapted to engage a series of ivoted pawls 26 mounted upon pins or stu shafts 27 extending from the outer face of the gear 21, which pawls are normally held in egagement with the ratchet teeth by springs Y The periphery of the rim of the gear 24 is formed with spur teeth meshing with a pinion 29 on a stub shaft 30, which pinion is integral with a spur gear 31 rotating therewith on said shaft and driven by a worm 32 on the adjacent end of the driving shaft 2. As the pull of the warp threads is mainly on the roll 18 the roll 17 is positively connected therewith by the gears 20 and 21 in order to positively drive said roll 17 at a regulated speed with respect to the roll 18 and prevent slipping of said roll 17.

From the foregoing description, it will be understood that when the driving shaft 2 is in motion, the gears 29 and 31 will be directly driven therefrom, and the pinion 29 will transmit motion to the gear 24. This gear 24 regulates the-let-oif or feed motion of the gear 21 and the rollers 17 and 18, which gear 21 and rollers 17 and 18 are actuated for the let-oli' motion under the pull of the warp threads, which are drawn inwardly by the take-up rollers and the beating in mechanism. The shaft 2 rotating to the right or in the direction shown by the arrow in 1, turns the gear 29 and gear 31 to the left, whereby the gear 24 is driven in an inward direction or to the right at the pro r rate of s d to regulate the let-off motion of the said gear 24 and rolls 17 and 18, according to the number of picks desired per inch of cloth. The ratchet teeth 25 of this ear 24 are of conventional construction, ha beveled or inclined surfaces and abutting shoulders, which latter are, however', ed at the forward ends of the beveled. sur aces in the direction of motion of said gear. As the gear 24 rotates forwardly at a timed rate of speed, and the lear 21 and rollers 17 and 18 rotate under e pull of the threads, the teeth of the awls 26 carried by the gear 21 en age the oulders of the ratchet teeth o the gear 24, whereby the forward rotation of the r 21,

and consequentl of the rollers 17 an 18, at a greater rate o speed than that of the gear 24 is prevented, whereby the excess feed of the warp threads by the let-olf mechanism under the pull upon the warp threads from the take-up roller and beating mechanism is avoided. The feed of the warp threads will, accordingly, be regulated by the diameter and speed of rotation of the ear 24, and the pawl and ratchet connection tween the lsame and the gear 21 acts in the nature Aof a clutch device, which prevents the forvward rotation of the gear 21 at greater speed than the speed of rotation of ear 24 while pei-mi said gear 21 to be acked at any time to aw back the warp threads, the

' 'j pawls 26 in the draw-back motion sliding over the inclined faces and shoulders of the ratchet teeth. The warp threads from the roll 15 will pass upwar y an rearwardly around the rolls 17 and then upwardly and forwardly around the roll 1.8, thereby insuring a proper feed action of said threads, while maintaining them under a proper tension. By the use of interchangeable gears 24 of different sizes the feed of the warp threads may be regulated for any desired number of picks per inch of cloth. Through the clutch connection formed by the pawl and ratchet teeth of the gears 21 and 24, the gear 21 will be allowed under the pull of the Warped threads to positively rotate forwardly with the gear 24 when the let-olf mechanism is in operation, the engagement with the shoulders of the ratchet teeth preventin said gear 21 from turning at a greater rate o speed than said gear 24, while it also permits such gear 21 to be turned rearwardly when said mechanism is out of operation to enable the weaver to hold the war threads back several inches at a time after picking out any amount of the threads to correct imperfections in the weaving o eration. It will be observed that the 'cran 2 and lever 12 are arranged at the front end of the loom frame, and, that by-the arrangement of the clutch mechanism and drive gearing shown, the let-olf mechanism may be thrown into and out of operation and the shaft 2 turned by the crank 2 when the clutch is disconnected, to turn back the threads whenever desired, without the necessit of the operator going back to the rear en of the loom.

It will thus be seen that our invention provides a let-o mechanism which is simple and eective in construction, permits the warp threads to be readil pulled back for the purpose described, an insures a proper feed of the threads under the nry tension at all times during the weaving operation without the necessity of employing auxiliary tensioning or e up means requiring manual mani ulation. As a result, any imperfect tensioning of the threads, such as occur in the use of manually adjustable take up means, is avoided, thus preventing to a large extent liability of the breaks of the warps in the weaving process. 'le we have shown a certain means for transmitting power to the driving gear of the leto' mechanism from the loom driving mechanism, any other gearin suitable for the purpose may be employ 1. In av let-0E mechanism for looms, the combination of a loom driving mechamsm including a main drive shaft, a warp roll having a let-o motion solely under the feed pill o the warp threads by the take-up and ting-inl devices, rimary and secondary guide rolls, intermes rs fixed to said ide rolls, a feed contro r loose on t e shaft of the secondary e roll alo side the gear thereon an provided wit internal ratchet' teeth, an auxiliary drive shaft in gear with said feed controlling gear for imparting a regulated and potive feed motion thereto, means for throwing said auxiliary drive shaft into and out of gear with the main drive shaft, pawls carried by the ear on the secondary guide roll for coperation with the ratchet teeth of the feed controlling gear, whereby the guide rolls and war roll are adapted to rotate for a let-olf action at a fixed speed controlled by the speed of said controlling gear and are coupled to said controlling gear for a reverse action to impart backward motion to the warp threads, and means for manually operating said auxiliary drive shaft for imparting backward motion to said guide rolls through the feed controlling gear when said auxiliary drive shaft is disconnected from the main drive shaft.

2. In a let-off mechanism for looms, the combination of a loom driving mechanism including a main drive shaft, a warp roll freely revoluble for a let-off motion solely under the feed pull of the warp threads by the itake-up and beating-in devices, primary and secondary guide rolls, intermeshing gears fixed to said rolls, a feed controlling gear loose on the shaft of the secondary guide roll alongside of the gear thereon and provided with internal ratchet teeth, an auxiliary drive shaft having at one end a drive gear meshing with said feed controlling gear for imparting a positive feed controlling motion thereto, spring actuated pawls on the gear of the secondary guide roll coperating teeth of the feed controlling gear to adapt said guide rolls and warp roll to have a letof motion at a speed controlled by the speed of said feed controlling gear, and to adapt said guide rolls to be reversely turned for imparting a backward motion to the warp threads, an elongated hollow shaft inclosing a portion of the auxiliar drive shaft and in gear at one end with t emain drive shaft, clutch mechanism at the take-up end of the loom for throwing said hollow shaft into and out of gear with the auxiliary drive shaft, and an operating handle upon the auxiliary drive shaft the loom, whereby said auxiliary drive shaft, when thrown out of gear with the main drive shaft, may .be turned in a reverse direction to transmit motion through the feed controlling gear to the guide rolls to feed the warp threads backwardly.

In testimony whereof we alix our signatures in Athe presence of two witnesses.

JOHN H EREENHALGH. HARRY GREENHALGH.'

Witnesses FRED. DIoKs, JOSEPH DUNN.

with the internal ratchet at the take-up end of 

